The present invention relates to a rapping mechanism and system for an electrostatic precipitator, the rapping system being of the mechanical type and characterized by having the capability of providing relatively high intensity raps if desired.
Electrostatic precipitators are widely employed, particularly among industrial users, for removing particulate from gases. A typical large electrostatic precipitator includes a housing in which banks of vertically extending collecting electrode plates or curtains are disposed, with particulate-laden gas passing through the housing parallel to the plates. The particulate carried by the gas stream is charged to one polarity by means of a corona discharge, and the collecting electrode plates are oppositely charged. The charged particles are therefore electrostatically attracted to the collecting electrodes. Additionally, some particles are attracted to the discharge electrodes which generate the corona discharge.
In order to remove the collected particulate from the electrodes, rapping or vibrating devices are commonly employed. In a large precipitator, there are a plurality of individual rapping devices, each rapping device shocking or vibrating an electrode group comprising one or more electrode plates or discharge electrodes. Collected particulate is dislodged by the vibration and falls by gravity to a sump or the like for removal.
It is an object of the present invention to provide a mechanical rapping system of the type which lifts and then releases weights which then freely fall by gravity impact on precipitator elements mechanically attached to collecting or discharge electrodes to impart mechanical vibration thereto.
It is another object of the invention to provide such a rapping mechanism which is characterized by having long term reliability, while lifting and releasing relatively heavy weights, for example, twenty pound (9.1 kg) weights.
It is still another object of the invention to provide a system including a plurality of individual rapping mechanisms which release their respective weights to effect rapping at different times.
It is still another object of the invention to provide a system including the provision to adjust the height to which the weight is lifted, by simple means and it is still another object of the invention to provide a system that effects a quick release of the driver system when the chosen lift height is attained.